This Presidential Young Investigator award will help Dr. Dean continue his work in temporal reasoning under uncertainty, for which he won a best-paper prize at the 1988 AAAI Conference, as well as time-dependent planning, mobile robotics, computer vision, and spatial reasoning. Dr. Dean's background combines artificial intelligence, control theory, operations research, and statistics. He also combines theoretical sophistication with practical skills, and shows talent in research management and technical writing.